Abstract

The genome of somatic cells is susceptible to change through ontogeny. These variations can take a variety of forms and occur
through different mechanisms. Stochastic intercellular variations of the genome are suggested to be involved in a number of
critical biological processes (pre‐natal development, cell number regulation, cell death and aging). However, somatic genome
variations have been shown to be involved in pathogenesis of a broad spectrum of human diseases (from chromosomal and monogenic
diseases to complex disorders). Nonetheless, the contribution of somatic genome variations to human biodiversity and disease
is usually underappreciated. The latter is due to consistent questioning the possibility of techniques used for uncovering
somatic genome variation. Therefore, technological aspects of studying intercellular variation of the human genome remain
an additional important issue for understanding the role of somatic mosaicism in health and disease.

Key Concepts:

The cellular genome is highly variable both at molecular and at chromosomal level.

Somatic variation of the human genome is a likely mechanism for biodiversity either at intercellular or at interindividual
level.

A number of critical biological processes (pre‐natal development, cell number regulation, cell death and aging) seem to be
mediated by somatic genome variations.

According to current concepts, the commonest type of intercellular genome variations are those manifested as changes of chromosome
numbers (aneuploidy or polyploidy).

Somatic genome variations are known to contribute to pathogenesis of hereditary and chromosomal diseases.

Intercellular genome variation is a highly probable mechanism of complex disorders (i.e. diseases of the brain and immune
system), pre‐natal mortality and cancer.

Understanding of the way to uncover somatic genome variations is an important issue for determining the contribution to intercellular/interindividual
diversity in health and disease as well as their functional consequences.